Method of growing ingot and ingot

ABSTRACT

Provided is a method of growing an ingot. The method of growing the ingot includes melting a silicon to prepare a silicon melt solution, preparing a seed crystal having a crystal orientation [110], growing a neck part from the seed crystal, and growing an ingot having the crystal orientation [110] from the neck part. The neck part has a diameter of about 4 mm to about 8 mm.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a national phase application of P.C.T.application PCT/KR2012/010332 filed Nov. 30, 2011, which claims thepriority benefit of Korean patent application 10-2012-0041987 filed Apr.23, 2012, the disclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a method of growing an ingot and aningot.

2. Description of the Related Art

Generally, a process of manufacturing a wafer for manufacturing asemiconductor device may include a slicing process for slicing a siliconmonocrystalline ingot, an edge grinding process for rounding an edge ofthe sliced wafer, a lapping process for planarizing a rough surface ofthe wafer due to the slicing process, a cleaning process for removingparticles and all sorts of contaminants which are attached to a surfaceof the wafer during the edge grinding or lapping process, a surfacepolishing process for securing a shape and surface suitable for postprocesses, and an edge polishing process with respect to the edge of thewafer.

Silicon monocrystalline ingots may be grown through a czochralski (CZ)method or a floating zone (FZ) method. The CZ method is commonly usedfor growing silicon monocrystalline ingots because large-diameter singlemonocrystalline ingots are capable of being manufactured through the CZmethod, and also the CZ method is relatively inexpensive method.

The CZ method may be performed by immersing a seed crystal in siliconmelt solution and then lifting the seed crystal at a low speed.

However, products having new crystal orientations are required toovercome limitation of existing semiconductor devices. For example, aproduct having a crystal orientation [110] is expected as a nextgeneration product. However, when compared to an ingot having crystalorientation [100], an ingot having the crystal orientation [110] havelow crystalline because a dislocation is propagated in a crystal growthdirection, and also, it is difficult to control the dislocation.

SUMMARY OF THE CLAIMED INVENTION Technical Problem

Embodiments provide a high-quality wafer having a crystal orientation[100].

Technical Solution

In one embodiment, a method of growing an ingot includes: melting asilicon to prepare a silicon melt solution; preparing a seed crystalhaving a crystal orientation [110]; growing a neck part from the seedcrystal; and growing an ingot having the crystal orientation [110] fromthe neck part, wherein the neck part has a diameter of about 4 mm toabout 8 mm.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features will be apparent fromthe description and drawings, and from the claims.

Advantageous Effect

According to the method of growing the ingot, the high-quality ingothaving the crystal orientation [110] may be grown. That is, the waferhaving the new crystal orientation which is capable of overcoming thelimitations of the semiconductor device according to the related art maybe manufactured. That is, the wafer having the improved deviceefficiency may be manufactured using the ingot having the crystalorientation [110].

Particularly, the boron concentration of the seed crystal may correspondto the doping concentration of the silicon melt solution. Therefore, anoccurrence of the misfit due to a concentration difference between thesilicon melt solution and the seed crystal may be controlled. The misfitdislocation represents a dislocation occurring within the seed crystalwhen the seed crystal contacts the silicon melt solution due to aconstant different therebetween in a case where the doping concentrationof the silicon melt solution is different from that of the seed crystal.In the embodiment, the misfit dislocation may be controlled to grow themonocrystalline having high quality

Also, since the neck part grown by the method of growing the ingotaccording to the embodiment has a diameter greater than that of the neckpart according to the related art, the neck part may support thelarge-size high-weight ingot. That is, the process failure may beprevented, and the process yield may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating a method of growing an ingotaccording to an embodiment.

FIG. 2 is a perspective view of an ingot manufactured through the methodof growing the ingot according to an embodiment.

FIG. 3 is a cross-sectional view of an apparatus for manufacturing aningot which is used for a method of growing an ingot according to anembodiment.

FIG. 4 is a graph illustrating experimentation data with respect to adislocation length to a neck part diameter in a method of growing aningot according to an embodiment.

DETAILED DESCRIPTION

In the drawings, the thickness or size of each layer (film), eachregion, each pattern, or each structure is modified for convenience indescription and clarity. Thus, the size of each element does notentirely reflect an actual size.

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings.

Referring to FIGS. 1 and 2, a method of growing an ingot according to anembodiment and an ingot manufactured by the method will be describedbelow in detail. FIG. 1 is a flowchart illustrating a method of growingan ingot according to an embodiment. FIG. 2 is a perspective view of aningot manufactured through the method of growing the ingot according toan embodiment.

A method of growing an ingot according to an embodiment includespreparing a melt solution (ST100), preparing a seed crystal (ST200),growing a neck part (ST300), and growing an ingot (ST400).

In the preparing of the melt solution (ST100), a silicon melt solutionmay be prepared in a quartz crucible installed within a chamber. Thatis, in the preparing of the melt solution (S100), silicon may be meltedto prepare a silicon melt solution. The silicon melt solution may have adoping concentration of about 8.5×1018 atoms/cm3 to about 1.7×1019atoms/cm3. Particularly, the silicon melt solution may be doped withboron. Here, the boron may have a concentration of about 8.5×1018atoms/cm3 to about 1.7×1019 atoms/cm3. In the boron dopingconcentration, boron may be heavily doped for determining anEPI-substrate, but not a general specific resistance band.

Particularly, in the preparing of the melt solution (ST100), a magneticfield may be applied. Particularly, the magnetic field may be appliedinto a lower side from a surface of the silicon melt solution. Moreparticularly, if a level of the surface of the silicon melt solution iszero, the maximum magnetic field may be applied into a positioncorresponding to a level of about −100 mm from the zero. The magneticfield may have intensity of about 1,500 G to about 3,500 G. As a result,a temperature deviation of the silicon melt solution may be reduced.Thus, the dislocation may be controlled.

In the preparing of the seed crystal (ST200), a seed crystal having acrystal orientation [110] may be prepared. Thus, an ingot having thecrystal orientation [110] may be grown from the seed crystal.

The seed crystal may have a boron concentration of about 8.5×1018atoms/cm3 to about 1.7×1019 atoms/cm3. That is, the boron concentrationof the seed crystal may correspond to the doping concentration of thesilicon melt solution. Therefore, an occurrence of a misfit due to aconcentration difference between the silicon melt solution and the seedcrystal may be controlled. The misfit dislocation represents adislocation occurring within the seed crystal when the seed crystalcontacts the silicon melt solution due to a constant differenttherebetween in a case where the doping concentration of the siliconmelt solution is different from that of the seed crystal. In the currentembodiment, the misfit dislocation may be controlled to grow amonocrystalline having high quality.

Next, in the growing of the neck part (ST300), the neck part may begrown from the seed crystal. That is, the neck part N having a thin andlong shape may be grown from the seed crystal.

In the growing of the neck part (ST300), the neck part may have a growthrate of about 3.0 mm/min to about 3.2 mm/min. Thus, the neck part may bequickly grown than a dislocation velocity to control the dislocation.

If the neck part has a growth rate of about 2 mm/min or less, the neckpart may be increased in diameter. Thus, it may be more difficult tocontrol the dislocation of the neck part in a [110] crystal. On theother hand, if the neck part has a growth rate of about 4 mm/min ormore, the neck part may be decreased in diameter. Thus, the neck partmay be vulnerable to a weight. Thus, the neck part may have a growthrate of about 3 mm/min to about 3.2 mm/min.

Referring to FIG. 2, the neck part N may have a length t of about 400 mmor more. Also, the neck part N may have a diameter d of about 4 mm toabout 8 mm. Since the neck part N has a diameter greater than that of aneck part according to a related art, the neck part N may support alarge-size high-weight ingot. That is, process failure may be prevented,and process yield may be improved.

In detail, if the neck part has a diameter less than about 4 mm, theneck part may not endure a weight of a large scale ingot having adiameter of about 300 mm or more during the growth of the ingot. Thus,the neck part may be broken to cause loss. Also, if the neck part has adiameter greater than about 8 mm, it may be difficult to control thedislocation of the neck part.

A reason in which the neck part has a diameter of about 4 mm to about 8mm and a length of about 400 mm or more will be described with referenceto following experimentation results.

Table below illustrates results obtained by arranging a dislocationlength according to a diameter of the neck part. FIG. 4 illustrates theexperimentation data of Table of FIG. 4 as a graph.

TABLE 1 Neck Dislocation Orientation Diameter length [110] 2.9 175 2.9165 3.0 220 3.0 230 3.0 230 5.92 270 6.81 350 6.24 280 5.98 300 6.48 3906.82 400 5.1 320 5.98 300 5.92 270

Referring to Table 1 and FIG. 4, when the neck part has a length lessthan about 400 mm, the dislocation length is short. Thus, althoughproductivity is improved, it may be difficult to control the dislocationin the [110] crystal. As a result, products may be deteriorated inquality.

Thus, it may be necessary that the neck part has a length of about 400mm or more so that the neck part has a diameter of about 4 mm to about 8mm to more easily control the dislocation.

In the growing of the ingot (ST400), an ingot I may be grown from theneck part N. That is, an ingot having a crystal orientation [110] may begrown. That is, a wafer having a new crystal orientation which iscapable of overcoming the limitations of the semiconductor deviceaccording to the related art may be manufactured. That is, a waferhaving improved device efficiency may be manufactured using the ingothaving the crystal orientation [110].

In the growing of the ingot (ST400), the ingot may have a lifting speedof about 0.9 mm/min or more. Thus, a cooling rate of the crystalline maybe increased by a growth apparatus including a cooler to improve heatresistance. Also, the dislocation may be multiplied to confirm whether apolycrystalline exists with a naked eye, thereby securing themonocrystalline.

The growing of the ingot (ST400) may include a shouldering formationprocess for expanding a diameter of the neck part N to a target diameterand a body growth process for growing the silicon monocrystalline ingotwhile maintaining the target diameter.

Hereinafter, an apparatus for manufacturing an ingot by using a methodof growing an ingot according to an embodiment will be described. FIG. 3is a cross-sectional view of an apparatus for manufacturing an ingotwhich is used for a method of growing an ingot according to anembodiment.

Referring to FIG. 3, an apparatus for growing a silicon monocrystallineingot according to an embodiment may be an apparatus used in a CZ methodof methods for manufacturing a silicon wafer.

An apparatus for growing a silicon monocrystalline ingot according to anembodiment includes a chamber 10, a first crucible 20 for containing araw material, a cover part 100, a second crucible 22, a cruciblerotation shaft 24, a lifting mechanism 30 for lifting an ingot, a heatshield 40 for blocking heat, and a resistance heater 70, an insulator80, and a magnetic field generation device 90.

These detailed descriptions are as follows.

Referring to FIG. 3, the first crucible 20 may receive a raw material.The first crucible 20 may receive a polysilicon. Also, the firstcrucible 20 may receive a melting silicon in which the polysilicon ismelted. The first crucible 20 may include quartz.

The second crucible may support the first crucible 20. The secondcrucible 22 may include graphite.

The first crucible 20 may be rotated in a clockwise or counterclockwisedirection by the crucible rotation shaft 24. The lifting mechanism 30 towhich a seed crystal is attached may be disposed above the firstcrucible 20 to lift the see crystal. The lifting mechanism 30 may berotated in a direction opposite to the rotation direction of thecrucible rotation shaft 24.

The seed crystal attached to the lifting mechanism 30 may be immersedinto a silicon melt solution SM, and then the lifting mechanism 30 maybe rotated to lift the seed crystal. As a result, a siliconmonocrystalline may be grown to manufacture an ingot I.

Sequentially, the resistance heater 70 for applying heat into the firstcrucible 20 may be disposed adjacent to the second crucible 22. Theinsulator 80 may be disposed outside the resistance heater 70. Theresistance heater 70 supplies heat for melting the polysilicon toproduce the silicon melt solution SM. Also, during the manufacturingprocess, the resistance heater 70 may continuously supply heat into thesilicon melt solution SM.

The silicon melt solution SM contained in the first crucible 20 may havea high temperature. Thus, heat may be released from an interface of thesilicon melt solution SM. Here, if a large amount of heat is released,it may be difficult to maintain a proper temperature required forgrowing the silicon monocrystalline ingot. Thus, the heat released fromthe interface may be minimized, and also, it may prevent the heat frombeing transferred into an upper portion of the silicon monocrystallineingot. For this, the heat shield 40 may be provided so that each of thesilicon melt solution SM and the interface of the silicon melt solutionSM are maintained at a high temperature.

The heat shield 40 may have various shapes so as to maintain thermalenvironments into a desired state to stably grow the crystal. Forexample, the heat shield 40 may have an empty cylindrical shape tosurround the periphery of the silicon monocrystalline ingot. Forexample, the shield 40 may include graphite, graphite felt, ormolybdenum.

The magnetic field generation device 90 which applies a magnetic fieldinto the silicon melt solution SM to control convection current of thesilicon melt solution SM may be disposed outside the chamber 10. Themagnetic field generation device 90 may be a device which generates amagnetic field in a direction perpendicular to a crystal growth axis ofthe silicon monocrystalline ingot, i.e., a horizontal magnetic field(MF). In the current embodiment, the magnetic generation device 90 mayacts from the process for melting the silicon. Particularly, themagnetic field generation device 90 may apply the magnetic field into alower side of a surface of the silicon melt solution.

A particular feature, structure, or effects described in connection withthe embodiment is included in at least one embodiment of the invention,and is not limited to only one embodiment. Further, when a particularfeature, structure, or characteristic is described in connection withany embodiment, it is submitted that it is within the purview of oneskilled in the art to effect such feature, structure, or characteristicin connection with other ones of the embodiments. Therefore, contentswith respect to various variations and modifications will be construedas being included in the scope of the present disclosure.

INDUSTRIAL APPLICABILITY

Since the apparatus and method for growing the ingot is available in thecurrent embodiment, industrial applicability may be high.

What is claimed is:
 1. A method of growing an ingot, the methodcomprising: melting a silicon to prepare a silicon melt solution;preparing a seed crystal having a crystal orientation [110]; growing aneck part from the seed crystal; and growing an ingot having the crystalorientation [110] from the neck part, wherein the neck part has adiameter of about 4 mm to about 8 mm.
 2. The method according to claim1, wherein the silicon melt solution has a doping concentration of about8.5×10¹⁸ atoms/cm³ to about 1.7×10¹⁹ atoms/cm³.
 3. The method accordingto claim 2, wherein the silicon melt solution has a boron concentrationof about 8.5×10¹⁸ atoms/cm³ to about 1.7×10¹⁹ atoms/cm³.
 4. The methodaccording to claim 1, wherein the seed crystal has a dopingconcentration of about 8.5×10¹⁸ atoms/cm³ to about 1.7×10¹⁹ atoms/cm³.5. The method according to claim 4, wherein the seed crystal has a boronconcentration of 8.5×10¹⁸ atoms/cm³ to about 1.7×10¹⁹ atoms/cm³.
 6. Themethod according to claim 1, wherein the neck part has a length of about400 mm or more.
 7. The method according to claim 1, wherein, in thegrowing of the neck part, the neck part has a growth rate of about 3.0mm/min to about 3.2 mm/min.
 8. The method according to claim 1, wherein,in the growing of the ingot, the ingot has a lifting speed of about 0.9mm/min or more.
 9. The method according to claim 1, wherein, in thepreparing of the silicon melt solution, a magnetic field is applied. 10.The method according to claim 9, wherein the magnetic field is appliedinto a lower side of a surface of the silicon melt solution.
 11. Themethod according to claim 9, wherein the magnetic field has an intensityof about 1,500 G to about 3,500 G.
 12. An ingot having the crystalorientation [110], the ingot being grown according to claims 1 to 11.